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Re: Compression ratio of HPACK.

From: 山本和彦 <kazu@iij.ad.jp>
Date: Sat, 01 Feb 2014 06:44:14 +0900 (JST)
Message-Id: <20140201.064414.1250069648688261654.kazu@iij.ad.jp>
To: jpinner@twitter.com
Cc: adrian.f.cole@gmail.com, ietf-http-wg@w3.org
Jeff,

> Just to sanity check I navigated to www.google.com -- the page load made 11
> requests, each with the same 8 identical cookies. Thus the reference set in
> this example saves 8 bytes per frame (as opposed to the 1.57 bytes in your
> analysis).

I think you should also consider how many headers are different (to be
deleted and be added). See the following example:

Old   New
1         to be deleted
2         to be deleted
3     3   common
4     4   common
5     5   common
6     6   common
      7   to be added

In this case, we cannot save four bytes. We need to sent two bytes for
deleting and one byte for adding. So, we can save just one byte.

P.S.

Even we can save 8 bytes in average in the real world, I don't think
it contributes to reduce the number of IP packets to be generated.

--Kazu
Received on Friday, 31 January 2014 21:44:45 UTC

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